Correlation between serological and mucosal inflammatory responses to Helicobacter pylori

In 82 patients who underwent gastroduodenoscopy, acute and chronic gastric mucosal inflammation was scored for severity, and systemic humoral immune responses to Helicobacter pylori antigens were assessed by enzyme-linked immunosorbent assays. On the basis of culture, gastric histology, and serologic evaluation, 33 patients were classified as H. pylori infected and 36 were classified as uninfected. Thirteen patients had negative cultures and stains but were seropositive and were analyzed separately from the other two groups. Specific serum immunoglobulin G (IgG) subclass responses to H. pylori whole-cell antigens and specific IgG responses to the 54-kDa heat shock protein homolog (Hp54K) and vacuolating cytotoxin were significantly greater in infected than in uninfected patients as were specific IgA responses to whole-cell antigens and cytotoxin (P < 0.001). Among the H. pylori-infected persons, serum IgG responses to Hp54K and to the vacuolating cytotoxin were correlated with acute mucosal inflammatory scores. In contrast, serum IgA responses to whole-cell sonicate and to vacuolating cytotoxin were inversely related to chronic inflammatory scores. By multivariant regression analysis, only specific serum IgG responses to Hp54K correlated with severity of inflammation (both acute and chronic; P < 0.001); these responses may be markers of inflammation or these antibodies could play a direct role in the pathogenesis of H. pylori-induced inflammation.

Divergence of genetic sequences for the vacuolating cytotoxin among Helicobacter pylori strains

Approximately 50% of Helicobacter pylori isolates produce a cytotoxin in vitro that induces vacuolation of eukaryotic cells. Screening a lambda ZapII library of H. pylori 60190 chromosomal fragments permitted the identification of a 3864-base pair (bp) open reading frame (vacA) that encoded the vacuolating cytotoxin, and a > or = 567-bp upstream gene that was homologous to Escherichia coli cysteinyl-tRNA synthetase. The sequence data suggest that a 33-amino-acid leader sequence and a C-terminal peptide are cleaved from a 139-kDa protoxin to yield the mature 87-kDa cytotoxin. The vacA gene product contains a C-terminal motif that is present in several other bacterial proteins that undergo C-terminal cleavage, including IgA proteases of Haemophilus influenzae and Neisseria gonorrhoeae. Isogenic H. pylori mutants with insertional mutation of the vacA gene lacked vacuolating cytotoxin activity and failed to produce the 87-kDa protein. Southern analysis of naturally occurring tox-H. pylori strains with vacA probes indicated the presence of hybridizing bands, but both Southern analysis and polymerase chain reaction studies suggested that the vacA sequences of tox- strains differed from those of tox+ strains. Sequence analysis of a 1541-bp region of polymerase chain reaction-amplified vacA from tox- strain 87-203 indicated 64.8% amino acid identity with the corresponding region from tox+ strain 60190. Thus, sequence divergence in vacA genes may explain the lack of functionally active cytotoxin production by some H. pylori isolates.

Correlation between vacuolating cytotoxin production by Helicobacter pylori isolates in vitro and in vivo

Approximately 50 to 60% of Helicobacter pylori isolates produce a vacuolating cytotoxin in vitro. To assess cytotoxin production in vivo, we sought to determine whether infection with a Tox+ H. pylori strain is associated with the presence of serum antitoxin antibodies. H. pylori isolates and serum samples were obtained from 30 patients, and serum samples were obtained from 20 uninfected patients as controls. Sera were tested by enzyme-linked immunosorbent assay for reactivity with the purified 87-kDa vacuolating cytotoxin, and the 30 H. pylori isolates were tested for vacuolating cytotoxin production. Supernatants from 14 (47%) of the 30 H. pylori isolates induced vacuolation of HeLa cells. Sera from the 30 H. pylori-infected patients reacted with the purified 87-kDa cytotoxin to a greater extent than sera from the uninfected controls for both immunoglobulin G (IgG) and IgA classes (P = 0.0004 and P < 0.0001, respectively). Serum IgG and IgA responses to the purified 87-kDa cytotoxin were higher among the 14 patients infected with Tox+ strains than among the 16 patients infected with Tox- strains (mean optical densities +/- standard errors of the means of 0.603 +/- 0.11 versus 0.234 +/- 0.07 [P = 0.005] and 0.644 +/- 0.12 versus 0.341 +/- 0.08 [P = 0.04] for IgG and IgA, respectively). Infection with a Tox+ strain compared with a Tox- strain was associated with increased antral polymorphonuclear leukocyte inflammation scores (P = 0.04). These data indicate that cytotoxin production by H. pylori isolates in vitro correlates with cytotoxin production in vivo and that infection with Tox+ H. pylori isolates may be associated with increased antral mucosal polymorphonuclear leukocyte infiltration.

Helicobacter pylori infection in Japanese patients with adenocarcinoma of the stomach

To examine the association of Helicobacter pylori infection with adenocarcinoma of the stomach in Japanese patients, we studied 29 patients and 58 matched controls. Ascertainment of H. pylori status was based on the presence of specific IgG to H. pylori. For the entire group, an association of this infection with gastric adenocarcinoma was suggested but not statistically significant. For patients in a putatively high-risk subgroup (non-cardia tumors and age < or = 70 years), the association was significant. Assays detecting serum IgA to whole H. pylori cells and cytotoxin, IgG to cytotoxin and Hp54K (the heat-shock protein homolog) and serum neutralization of cytotoxin activity each showed clear differences between H. pylori-infected and uninfected persons in this population. However, for none of these assays was there a significant difference between values for H. pylori-infected persons with or without gastric cancer. Thus, while H. pylori infection was associated with non-cardia gastric cancer in Japanese persons < or = 70 years of age, use of these additional serologic markers did not define additional factors that might be associated with increased risk.

Potentiation of Helicobacter pylori vacuolating toxin activity by nicotine and other weak bases

About 50% of Helicobacter pylori isolates produce a vacuolating toxin in vitro, which may be an important determinant of virulence. Because ammonium salts potentiate H. pylori toxin activity, the effect of other weak bases upon toxin activity was determined. Vacuolation of HeLa cells was quantitated using a neutral red uptake assay. As expected, ammonium chloride, trimethylamine, triethanolamine, and nicotine each induced vacuolation of HeLa cells when tested independently. In addition, each of these weak bases potentiated H. pylori vacuolating toxin activity, whereas sodium chloride or sodium hydroxide did not. Sequential incubation of cells with toxin followed by nicotine resulted in potentiation of vacuolation, whereas sequential incubation in the reverse order did not lead to potentiation. Monensin inhibited the formation of vacuoles by either H. pylori vacuolating toxin or nicotine. The potentiation of H. pylori toxin activity by ammonia and nicotine may contribute to gastroduodenal mucosal injury associated with this infection.

Serum neutralizing antibody response to the vacuolating cytotoxin of Helicobacter pylori

Approximately 50% of Helicobacter pylori isolates produce a cytotoxin in vitro that induces vacuolation of eukaryotic cells. To determine the in vivo relevance of this phenomenon, we sought to detect cytotoxin-neutralizing antibodies in sera from H. pylori-infected persons. As a group, sera from 29 H. pylori-infected patients neutralized the activity of the purified cytotoxin to a significantly greater extent than sera from 24 uninfected persons (P = 0.007). The cytotoxin neutralizing activity in sera from H. pylori-infected persons was mediated predominantly by the purified IgG fraction. Sera from H. pylori-infected persons neutralized the cytotoxins produced by multiple H. pylori strains, but failed to neutralize trimethylamine-induced cell vacuolation. Neutralization of cytotoxin activity by human or immune rabbit sera was associated with immunoblot IgG recognition of an 87-kD H. pylori protein. Similarly, neutralization of the toxin by sera was associated with IgG recognition of the purified cytotoxin in an enzyme-linked immunosorbent assay (P less than 0.0001). The presence of cytotoxin-neutralizing antibodies in sera from H. pylori-infected persons indicates that the cytotoxin is synthesized in vivo.

[Revascularization of the deep femoral artery in arterial insufficiency of the lower limbs. Clinical aspects and immediate results]

The main indications for revascularisation of the lower limb using the deep femoral artery are explained. In aorto-iliac disease with obstruction of the superficials, an aortofemoral by-pass is created, and the distal end of the prosthesis is sutured on the point of origin of the profunda in the form of a patch. In cases where the patients's local or general condition precludes the establishment of a femoro-popliteal by-pass in femoro-popliteal disease, endoarteriectomy is performed and a patch is applied from the CFA to the first segment of the profunda. Thirty-six cases in which the method described was applied are illustrated. These are culled from a total of 144 artery reconstructions performed in 1975--77. The results (33 asymptomatic cases 6 months after surgery, equal to 91.7%) are comparable with those obtained in by-passes with patent SFA in patients with aorto-iliac obstruction. In addition, the method often makes amputation unnecessary in patients with obstruction of the subinguinal trunks only, but unable to be treated by the establishment of a femoropopliteal by-pass.